JPS5828225B2 - Manufacturing method of hardened cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, attempts have been made to improve the strength of a hardened cement product by mixing glass fibers into cement and curing the mixture.

However, cement produces a large amount of slaked lime during hydraulic hardening, and because this lime corrodes the glass fibers, which are susceptible to alkalinity, the reinforcing effect could not be maintained over a long period of time.

When painting casings or cement-hardened materials such as slate, free Ca precipitates when the cement hardens.
Because of (0H)2, the paint did not spread well and had poor adhesion, resulting in defects such as peeling of the paint film.

The present invention was made for the purpose of improving the above-mentioned drawbacks.
03 ・3CaSO4・31~32 H20s or less TS
H), alumina component, glass fiber, and water, and further, other additives such as other fibrous reinforcing materials and fillers are mixed uniformly, then shaped and cured. The present invention provides a method for producing a cured fiber-reinforced cement body.

The present invention will be explained in detail below.

(1) The cements used in the present invention are generally referred to as cements such as Portland cement, blast furnace cement, white cement, and early-strength cement and have hydraulic properties.
This applies to all cements that liberate lime during hydraulic hardening.

(2) TSH can be obtained as follows; however, any method other than the methods exemplified below may be used, and the method for producing TSH is not limited.

(2) Obtain TSH by reacting an aqueous solution of aluminum sulfate with a CaO component.

■ OaO and Al2O3 are mixed at a molar ratio of 3=1 or a molar ratio close to this, and this is calcined at a high temperature of 900 to 1400°C to form so-called 03A [3CaO-A1203], and the required amount of stone is added to this. Coal is added and reacted in the presence of a large amount of water to obtain TSH.

■ 30aO+Al2O3・0aSO+・12H2
0 (calcium aluminate monosulfate hydrate, hereinafter abbreviated as MSH), stone powder is M
TSH is obtained by blending Oa 804 .2H20 so that the molar ratio is 1:2 or close to it, and reacting this in the presence of water.

Here, gypsum may also be anhydrous, semi-hydrous, or dihydrate gypsum.

(3) As the alumina component, aluminum oxide (A1
20a), alumina hydrate [gibsite, boehmite,
Diaspore, Piayarite, etc.], activated alumina 1,
Alumina hydrate hydrogen) 4 is used.

The above alumina components may be used alone or in combination.

(4) The molar ratio of TSH and alumina component is TSH/A1□
It is desirable to set the value to 03=1/2t or close to it.

The desirable range is that the alumina component is 1.0% per mole of TSH.
It is 0 to 3.0 moles.

The amounts of TSH and alumina components added vary depending on the amount of lime liberated from the cement, but for example, the total amount is 5 to 100 parts by weight (hereinafter referred to as "parts") of Portland cement.
It is appropriate to add 30 parts by weight; if the amount is below this range, the effect of addition will be small, and if it is above this range, the strength will tend to decrease.

(5) The glass fiber may be any commonly used reinforcing glass fiber, or may be an alkali-resistant glass fiber.

Glass fibers are not limited, but preferably added at 1.0φ to 2.0% 1 per 100 parts of Portland cement, and various lengths are used, for example, from 178 inches to 1 inch. be able to.

(6) In the present invention, other additives added as necessary include reinforcing fibers other than glass fibers,
Fillers, pigments, aggregates, etc. are used.

For example, inorganic fibers such as asbestos and rock wool, synthetic fibers (nylon, polyvinyl acetal, polyvinyl formal, polyester, etc.), and natural organic fibers (pulp, hemp, etc.) are used.

The amount of these additives to be added is determined depending on the intended use of the product or the manufacturing conditions.

For example, when a plate-shaped body is obtained by a papermaking method, asbestos fibers are added at a rate of 2 to 15%.

However, if the content of organic matter (for example, fiber) exceeds 20%, the flame resistance deteriorates, so it is not a good choice.

(7) The above raw materials are appropriately mixed, shaped, and cured.

The excipient means are not limited. For example, there are compression methods, extrusion methods, casting methods, and paper making methods.

The amount of water to be mixed is determined to be suitable for these shaping means.

For example, a slurry form is suitable for the casting method, and a white water form is suitable for the papermaking method.

The curing conditions after shaping are not limited.

Includes natural curing, moist heat curing, autoclave curing, etc.

Through the above steps, a reinforced cement hardened body according to the present invention is obtained.

(8) As explained above, the present invention uses ettringite [3CaO・Al2O3・3Ca Phantom 4・31
~32H20, hereinafter referred to as TSH], an alumina component, glass fiber, and water, and further, other additives such as other fibrous reinforcing materials and fillers are added and mixed uniformly, and then shaped. Since it is characterized by curing, the alkali in the cement is fixed, and even the glass fibers, which are weak against alkali, can provide a reinforcing effect, and since there is little alkali precipitation, the adhesion of paint is improved.

The reason why alkali in cement is fixed according to the present invention is not clear, but it is thought that it is because a reaction expressed by the following formula occurs, producing MSH and fixing lime.

30aOHA120g ・30aso, @31~32H
20+6CaO+2A1203-+ 3(30a041
203 ・Oa 804 ・12H20) Example 1 100 parts of Portland cement, 10 parts of silica sand (325 mesh free pass), 17.8 parts of TSH, 2.2 parts of aluminum hydroxide (Boehmai), 5 parts of glass fiber, asbestos 10 parts and 200 parts of water were mixed, this was made into a paper, and after making it into a 5mm thick paper using a making machine, it was made into a 4mm thick paper.
A fiber-reinforced cement sheet was obtained by natural curing for a week.

The strength of the obtained fiber-reinforced cement sheet is bending strength 5
80 kg/ca % Charpy impact strength is 27 [k
It was gbi/c-1,l.

Microscopic observation of the glass fibers exposed on the fractured surface of the test piece revealed that the appearance had hardly changed.

In addition, after painting, we observed the peeling state of the paint, and found that
The ``glue'' of the paint has been improved.

Beautiful Example 2 A sheet was formed using the same formulation and molding method as in Example 1.

In addition to this, a coating film containing 1 part of amorphous silica, 0.1 part of red iron oxide, 0.01 part of a dispersant (sodium tripolyphosphate), 0.01 part of a crack inhibitor (zirconium oxide), and 1 part of water. The slurry was applied to the excipient at a rate of 200 S'/7n2 and allowed to naturally cure.

(4 weeks). In this way, a very good coating film could be obtained.

When the pH of the solution after immersing the cured bodies obtained in Examples 1 and 2 in water for 2 days was measured, it was found to be slightly alkaline at 8 to 9.5, which was lower than the pH of 12 to 13 in the case of cement alone. It was found that the amount of free alkali in the hardened cement was reduced.

Claims (1)

[Claims] 1 Ettringite (30aO・Al2O) in cements
3"3CaSO," 31-32. H2O, hereinafter TS
H], alumina component, glass fiber, and water, and further, other additives such as other fibrous reinforcing materials and fillers are mixed uniformly, and then shaped and cured. A method for manufacturing a hardened glass fiber reinforced cement body.